Have funny idea.I just procured a 32 short RF low wall with a good bore.Planning on rechamber and convert to CF, have been wanting to make a 32 ideal short except .312, usually I'm after another 32 s&w long but since a low wall I could get more juice from it.

Then I had the thought, what if I breach seated either smokeless or BP, to increase capacity to that of a real 32 ideal case.

I have a 32 h&r mag reamer that I use for s&w chambers. The other thought is a 327 fed mag case used same way for maximum capacity.Just some wild thoughts.

Unsure of how breach seat throats are designed and different from a normal throat.

I had some fun with an old Bay State, chambered .32RF. I made a new link to align the firing pin for centerfire, so it could shoot .32 Long Colt. Not yet having the proper heeled bullets, I started breech seating some swaged hollow-base wadcutters I had handy. Worked like a charm. Those bullets being very soft I did not go for any hot loads. Throat wasn't altered in any way. At 30 yards they were minute of golf ball.

Occurs to me that you could use a .30 caliber throating reamer to follow up your H&R Mag reamer. The SAAMI throat for the .308 Winchester cartridge would be a good one, (as opposed to the .30-30 or .30-06 throats, neither of which are optimum by today's standards.) Pilot might be undersize unless you use a bit something to help center it.

There are two different types of reamers for the 32 H&R magnum: a pistol reamer, and a rifle reamer. The throats are different. The pistol reamer is for cutting chambers in a cylinder, and the rifle reamer is for use in a barrel. Brownell's sells pistol caliber chambering reamers for rifles. (I think they're made by Manson, but can't remember right now) If you use a pistol reamer for chambering a rifle, you might not get the accuracy that your looking for. You could use a throating reamer as was suggested, but the pistol reamer on it's own may or may not give the best results.